As a compound having a broad treatment spectrum for central neurological diseases such as schizophrenia and the like, for example, a compound represented by the following formula (1) (hereinafter compound (1)) has been reported (patent document 1).
wherein each symbol is as defined in patent document 1.
The above-mentioned compound (1) is an antipsychotic agent having a broader treatment spectrum as compared to conventional typical antipsychotic agents and atypical antipsychotic agents, causing less side effects, and superior in tolerability and safety. However, this compound is associated with problems in that its application to oil injections is limited and the like, since it is poorly soluble in oil such as sesame oil and benzyl benzoate. Oil injections are useful as compared to aqueous suspensions from the aspects of imparted blood concentration sustainability (control of diffusion in administration site by oily base), shortened liquid preparation time when in use (unnecessitated mixing and shaking), secured sterilization by filtration (oily base filtration), avoidance of physical stimulation at administration site (oily base stability), improved accuracy of filling into injection container (container filled with oily base) and the like.